Extended-life settable compositions are provided and, more particularly, extended-life settable compositions are provided that comprise red mud and water.
Settable compositions may be used in a variety of subterranean operations. For example, in subterranean well construction, a pipe string (e.g., casing, liners, expandable tubulars, etc.) may be run into a wellbore and cemented in place. The process of cementing the pipe string in place is commonly referred to as “primary cementing.” In a typical primary cementing method, a settable composition may be pumped into an annulus between the walls of the wellbore and the exterior surface of the pipe string disposed therein. The settable composition may set in the annular space, thereby forming a hardened, substantially impermeable annular sheath that may support and position the pipe string in the wellbore and may bond the exterior surface of the pipe string to the subterranean formation. Among other things, the annular sheath surrounding the pipe string prevents the migration of fluids in the annulus and protects the pipe string from corrosion. Settable compositions may also be used in remedial cementing methods to seal cracks or holes in pipe strings or annular sheaths, to seal highly permeable formation zones or fractures, or to place a cement plug and the like.
A broad variety of settable compositions have been used in subterranean cementing operations. In some instances, extended-life settable compositions have been used. In contrast to conventional settable compositions that set and hard upon preparation, extended-life settable compositions are characterized by being capable of remaining in a pumpable fluid state for at least about one day (e.g., about 7 days, about 2 weeks, about 2 years or more) at room temperature (e.g., about 80° F.) in storage. When desired for use, the extended-life settable compositions should be capable of activation and consequently develop reasonable compressive strengths. For example, an extended-life settable composition that is activated may set into a hardened mass. Among other things, extended-life settable compositions may be suitable for use in wellbore applications such as applications where it is desirable to prepare the settable composition in advance. This may allow the settable composition to be stored prior to use. In addition, this may allow the settable composition to be prepared at a convenient location before transportation to the job site. Accordingly, capital expenditures may be reduced due to a reduction in the need for on-site bulk storage and mixing equipment. This may be particularly useful for offshore cementing operations where space onboard the vessels may be limited.
While extended-life cement compositions have been developed heretofore, challenges exist with their successful use in subterranean cementing operations. For example, some extended-life settable compositions may have limited use at lower temperatures as they may not develop sufficient compressive strength when used in subterranean formations having lower bottom hole static temperatures. In addition, it may be problematic to activate some extended-life settable compositions while maintaining acceptable thickening times and compressive strength development. Moreover, supply/inventory constraints may restrict the availability of certain key components of extended-life settable compositions depending on geographic availability.